1. Field of the Invention
This invention relates to replaceable liquid reservoirs which contain liquids to be dispersed in atomizer devices; and more particularly it concerns novel sealing arrangements for such replacement reservoirs which reliably protect against leakage of liquid during transportation, storage and use.
2. Description of the Related Art
Replacement reservoirs which contain liquids to be dispersed in an atomizing device are known. These reservoirs generally comprise a bottle for containing the liquid, and a plug and wickholder which seals across the neck of the bottle. A wick extends from the liquid within the bottle and up through the plug and wickholder to deliver the liquid to the atomizing device.
It is important to provide a reliable and durable liquid seal between the bottle and the plug and wickholder during both storage and use and to provide a reliable and durable seal between the plug and wickholder and a removable sealing cap which covers the upper end of the wick during storage of the replaceable reservoir. Because many liquids which are dispersed in atomizer devices, such as fragrances and insecticides, have very low viscosity and are highly volatile, a generally tight interference fit is required between the mating parts of the reservoir in order to achieve reliable sealing. However the forces involved in forming an interference fit between the bottle and plug and wickholder should not interfere with the forces involved in forming an interference fit between the plug and wickholder and an overcap which seals around the wick during storage. That is, the forces involved in forming one seal should not cause stresses which affect the integrity of the other seal.
U.S. Pat. No. 6,293,474 describes an atomizing device in which liquid contained in a liquid container is drawn up through an open neck of the container by means of a wick to a vibrating orifice plate. A combination plug and wickholder closes the open neck of the container. This plug and wickholder is a unitary molded member which includes an inner vertical tubular wall for containing and supporting the wick, a radially extending horizontal wall which extends outwardly from the tubular wall, and an outer peripheral skirt which extends downwardly from the outer edge of the horizontal wall and clamps over a bead on the outer surface of the neck of the container. A tubular sealing wall projects downwardly from the undersurface of the horizontal wall and fits tightly inside and seals the neck of the container to seal the plug to the container.
U.S. Pat. Nos. 6,296,196, 6,341,732, 6,386,462, 6,382,522, 6,446,880 and 6,450,419 and assigned to the assignee of this application, describe an improvement to the earlier plug and wickholder wherein the horizontal wall portion between the tubular sealing wall and the wickholder is moved down to the lower portion of these elements so that they are connected to each other at the their lower edges. This exposes a large surface area on the outer surface of the tubular wickholder over which a tubular cap can fit to tightly to seal the wick from the atmosphere.
The present invention provides improvements which isolate the stresses which occur when a cap is mounted on and sealed to the plug and wickholder from the stresses which occur when the plug and wickholder are mounted on and sealed to the liquid container or reservoir. By virtue of this isolation, it becomes possible to provide high sealing forces for each seal, i.e. the seal between the cap and the plug and wickholder and the seal between the plug and wickholder and the liquid reservoir or bottle, without causing undue stresses which could cause cracking and leakage during assembly, shipping and storage.
The invention in one aspect involves a combination plug and wickholder comprising a unitary molded plastic piece. This plastic piece includes first and second generally vertical tubular walls, a generally horizontal upper wall, a circumferential skirt extending down from the upper wall and a generally cylindrical sealing wall extending down from the upper wall to press and seal against the inner surface of the neck of a liquid container. The first tubular wall contains and supports a wick extending up from within the container. The second tubular wall extends around and is concentric with the first wall. The first and second tubular walls are connected to each other near their lower ends. The horizontal upper wall, which is configured to be fitted over the top of a container or bottle neck, is integral with and extends radially outwardly from the second tubular wall near its upper end. The circumferential skirt extends down from the outer edge of the radially extending upper wall. The skirt is formed on its internal surface near the bottom edge thereof with latch elements to hold the skirt to the neck of a container or bottle. The generally cylindrical sealing wall extends down from the upper wall between the skirt and the second tubular wall for fitting inside of and becoming sealed to the inside surface of the container or bottle neck when the latch elements hold the skirt to the container or bottle neck. The cylindrical wall is free of other structure at its lower edge. By virtue of this configuration, the stresses caused by sealing a cap to the tubular wickholder and the stresses caused by sealing the cylindrical wall to the inner surface of the container or bottle are isolated from each other so that sealing of the one does not cause a danger of creating a leakage condition from the other. At the same time the stresses involved in attaching the plug and wickholder to the container or bottle are isolated so that the danger of cracking and consequent leakage is avoided.
The invention in another aspect involves a subassembly comprising a plug and wickholder as above described in combination with a removable sealing overcap. In a still further aspect the invention involves a subassembly comprising a plug and wickholder as above described mounted on a bottle such that a liquid to be dispersed is transferred from the bottle via a wick which extends through the plug and wickholder. In yet another aspect the invention involves a combination comprising a plug and wickholder, as above described, mounted on a bottle and a sealing overcap which encloses a wick extending from within the bottle and out through the plug and wickholder.